A device of said type is known from WO 2007/009279 A1. In said known high-pressure accumulator injection system for an internal combustion engine, each injection valve is assigned an accumulator chamber and a non-return valve with bypass throttle connected parallel thereto. The injection valves are connected by means of fuel lines to a high-pressure feed device. By virtue of each injection valve being assigned a non-return valve with bypass throttle connected parallel thereto, it is possible with said high-pressure accumulator injection system to realize stable and reproducible injection processes with an expedient pressure profile during every injection process, even if the discrete accumulator chambers have an unusually small volume. Said high-pressure accumulator injection system makes do without a large-volume common rail.
A further injection device is known from EP 1 108 886 A. The cylinder head of an internal combustion engine has inserted into it one injection valve for each combustion chamber. A bore runs through the cylinder head to each injection valve, in which bore is laid a pressure pipe. The housing of the injection valve has, at the side, a high-pressure sealing surface against which the pressure pipe bears by means of its high-pressure counterpart sealing surface integrally formed on the end at this side. The high-pressure supply line to each pressure pipe is formed by a single common rail which is fastened directly to the cylinder head by means of screws and brackets. The brackets form a structural unit with the common rail, which structural unit can be pressed for sealing against the pressure pipe by means of screws. A flow restrictor may be provided between the common rail and each pressure pipe, which flow restrictor is fastened to the common rail by means of a thread and bears, by means of its end facing away from the common rail, against the pressure pipe. The common rail, which forms the high-pressure supply line, forms an accumulator, which is common to all the injection valves, for the highly pressurized fuel. Common rails are dependent on the number of cylinders of the internal combustion engine, the configuration of the internal combustion engine and the power of the latter, and are therefore specific to every engine type.
To eliminate the associated disadvantages, it is proposed in EP 1 485 609 B1 that each injection valve, which has an accumulator chamber, have attached to it by means of a screw connection a tubular high-pressure connection piece which forms a further accumulator chamber. At the other side, the high-pressure connection piece is connected by means of a supply throttle to a duct for the fuel.
In a fuel injection system known from WO 03/027485 A1, a number of fuel injectors are charged with highly pressurized fuel by means of a high-pressure collecting chamber via high-pressure lines. The fuel injectors comprise an annular chamber into which a connection piece which holds the high-pressure line opens out. Held so as to be situated upstream of the injector as viewed in the flow direction, and assigned to the high-pressure supply line, is a secondary volume which comprises a hydraulic decoupling element at its side facing toward the distributor.
JP 2000-205081 A discloses an accumulator injection system in which fuel is supplied at high pressure to a common rail by means of a high-pressure pump. An auxiliary accumulator is connected between a distributor line, which is arranged downstream of the common rail, and a nozzle holder. The auxiliary accumulator has a capacity of 3 to 20 times the fuel quantity required for a full-load injection.
The fuel injection system known from DE 10 2004 055 266 A1 also provides, between a high-pressure fuel pump and the injectors, one pressure accumulator for each injector.
WO 03/076794 A1 discloses an injection system which has feed units for feeding fuel from a fuel reservoir for the supply of at least one high-pressure line to the cylinders of an internal combustion engine. A number of fuel injectors are supplied by means of the at least one high-pressure line, with said fuel injectors comprising line sections by means of which the individual fuel injectors are connected to one another. The injector bodies comprise an integrated accumulator chamber.
In the common rail injection system known from EP 0 921 303 A, the accumulator is connected directly by means of a bracket and a pressure pipe to the injector. Should relatively significant leakages occur in the injection system, a flow restrictor may be connected between the accumulator and bracket.
EP 1 353 063 A2 discloses a fuel injection system in which at least one injection nozzle, which is connected to a feed system, is provided for each cylinder of the internal combustion engine. The feed system has an associated fuel pressure accumulator for each cylinder.
The fuel injection system disclosed in DE 101 14 219 A1 for supplying fuel to the combustion chambers of an internal combustion engine has a high-pressure pump which charges a number of fuel injectors with highly pressurized fuel. The individual fuel injectors is assigned in each case an accumulator volume which is charged directly by the high-pressure pump via a high-pressure supply line.